1. Field of the Invention
The present invention relates to an air intake system for providing combustion air to an internal combustion engine.
2. Related Art
Internal combustion engines typically use air intake manifolding to provide both fresh air and recirculated exhaust gases (EGR) to the engine's cylinders. Typically, a throttle body is attached to the intake manifold by threaded fasteners. Because of the necessity for attaching various linkages and other devices to the throttle body, the throttle body is often subject to various pushing and pulling forces, some of which may cause the throttle body to move relative to the intake manifold. This movement is undesirable because it may cause the throttle body's fasteners to loosen, thereby permitting air to leak through the joint extending between the throttle body and the intake manifold. Such air leaks may be a problem because air leaking through the joint is not metered air. In other words, it is not air which has passed through an air flow meter and therefore the engine's control computer will not be able to account for the air; this could cause an issue with the engine's control system.
The problem of maintaining the throttle body in tight contact with an intake manifold is frequently exacerbated with the use of composite intake manifolds, because the composite materials are often more prone to creep and consequent loss of fastener tension.
It would be desirable to provide an intake system in which the intake manifold and throttle body have features which tend to prevent loosening of the throttle body upon the intake manifold.